Metformin may prevent skin cancer in all skin types

Key takeaways:

• Exposure to metformin lowered the risk for nonmelanoma skin cancer across skin types.
• However, it was not associated with reductions in squamous cell carcinoma risk among Black patients.

Metformin may have potential in preventing nonmelanoma skin cancer, including in most populations with skin of color, according to a study.

Studies around the world have found that metformin, a commonly used diabetes medication, has potential as a preventative for nonmelanoma skin cancer. According to a study conducted by Zaim Haq, BA, a medical student at The Warren Alpert Medical School of Brown University, and colleagues, metformin may be beneficial for preventing skin cancer due to underlying mechanisms such as its ability to restrict cancer cells’ access to essential energy and nutrients, inhibit cell growth, curtail cell division and tumor expansion and more.

“Despite these promising leads, there remains a significant gap in our understanding of the impact of metformin on squamous cell carcinoma [SCC] and basal cell carcinoma [BCC] risk, especially as it relates to patients with skin of color,” the authors explained.

Using the All of Us database, a tool which gathers health information on over a million Americans with special attention to those with diverse skin types, the researchers examined metformin’s potentially beneficial impact on protecting patients of all skin types against skin cancer.

They pulled information on 4,111 SCC and 8,047 BCC cases and compared them with 16,444 and 32,188 respective controls. Among the pooled SCC group, 90.93% were white, 1.7% were Black, 2.09% were Hispanic and 5.28% identified as “other.” Additionally, 57.41% were men and 40.67% were women. Race and ethnicities of the pooled BCC group included 91.61% white patients, 0.86% Black patients, 2.7% Hispanic patients and 4.83% “other” patients. Also, 51.27% were men and 46.91% were women.

Results showed that exposure to metformin was associated with a reduced risk for nonmelanoma skin cancer across skin types diagnosed with SCC and BCC with multivariable adjusted odds ratios of 0.45 (95% CI, 0.4-0.51) and 0.33 (95% CI, 0.29-0.36) in the respective groups.

The only exception to this benefit was found in Black patients where metformin exposure was not associated with significant reductions in SCC risk.

“This discrepancy could stem from the fact that SCC in these patients often develops in sun-protected areas and is strongly linked to chronic scarring and inflammation, factors that may not be influenced by metformin use,” the authors explained.

“While previous population-level studies have yielded mixed results, the nuanced variations among racial groups found in our study underscore the need for personalized approaches in evaluating metformin’s anti-cancer properties, emphasizing its potential significance in skin cancer prevention,” the authors concluded.